twalthr commented on a change in pull request #9545: [FLINK-13355][docs] Add documentation for Temporal Table Join in blink planner URL: https://github.com/apache/flink/pull/9545#discussion_r319482758
########## File path: docs/dev/table/streaming/temporal_tables.md ########## @@ -22,9 +22,13 @@ specific language governing permissions and limitations under the License. --> -Temporal Tables represent a concept of a (parameterized) view on a changing history table that returns the content of a table at a specific point in time. +Temporal tables represent a concept of changing table that its data is deemed to be effective or valid along some time period. -Flink can keep track of the changes applied to an underlying append-only table and allows for accessing the table's content at a certain point in time within a query. +The changing table can either be a changing history table which tracks the changes (e.g. database changelogs) or a changing dimension table which materializes the changes (e.g. database tables). + +For the changing history table, Flink can keep track of the changes and allows for accessing the content of the table at a certain point in time within a query. In Flink, this kind of table is represented by a *Temporal Table Function*. + +For the changing dimension table, Flink allows for accessing the content of the table at processing time within a query. In Flink, this kind of table is represented by a *Temporal Table*. In the future, a *Temporal Table* can also represents a changing history table. Review comment: Mention that results are not deterministic/not replayable. Remove the future sentence for now. This is future work. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
